Punching die set



June 1, 1965 J. H. BENNETT PUNGHING 151B SET Filed Nov. 1. 1961 INV EN TOR.

ATTNEYS 3,186,284 PUNCHING DIE SET John H: Bennett, Bridgeport, Conn., assignor to Minnie Punch & Die Company, Inc., Union Township, NJ., a corporation of New Jersey Filed Nov. 1, 1961, Ser. No. 149,379

, 7 Claims. (Cl. 83-7-623) pieces, generally referredgto as short-run quantities, has

heretofore been expensive and time consuming because of a number of factors. Thus while pieces may be made by individual-ly punching or drilling each perforation in each piece one at a time, naturally since each piecemust be handled as many times as it has perforations, such a procedure becomes increasingly expensive with each perforation required. To form allthe perforatio'ns atV once, as by making a die set, is alsoexpensiveparticularly for just short-run quantities as the dies` are approximately as expensive to manufacture as .long-runi dies made by tool and die makers. Moreover, adjustable punch and, die sets, while heretofore proposed for shortruns, have not been found completely satisfactory becauseof their initial expense, their loss of accuracy during use, the costlof making a template, limitations as to vcloseness of perforations, etc. Y

It is accordingly an object of the present invention to provide a die set that obviates the above'disadvantages for perforatiiig short-run quantitiesof pieces.

Another object of the present invention is to provide -`a short-run punching die set which is economical to fabrivcate and may be made by semi-skilled labor with a mini-V mum amount of operations instead oq'rlvrequiring tool and die makers. Y Y

A further object of the present invention is to provide a die set of the above-noted type which is reliable'and accurate in operation and which may be easily and simply maintained in working orderi An additional object of the present invention is to provide a punching die set which may be quickly and easily secured to a p-ress requiring little, if any, change in the .bed and ram plates of the press and which may be easily removed therefrom. p

InV carrying out the present invention, a feature resides in the forming of the die set by the use of a punch plate and a die plate. The' two plates are secured together in parallel relation for movement relative toward 'and away from each other. The punch plate has secured thereto the punches While the die plate is provided with die members that cooperate with the punches to punch the perforations in the piece.` By securing the die set to the ram of a punch press, the movement of the ram towards the steel 'pad causes compression of the punch plate and die plate to thereby punch the perforations in the piece positioned therebetween.

According to the present invention the punches and the die members are formed of a material that is referred toas prehardened though relatively easily machinable and has,l an approximate Rockwell hardness of C444. The punch and die plates are formed of a softer material such as aluminum. VThe die number and the punches are each lformed to have a head with anundercut or smaller collar. With this structure the punches and the die numbers are easily secured to their respective plates simply by exerting a compressive force thereon that forces each head into the United States Patent In the drawing: y FIGURE 1 is an elevation of the die set of theV p-resent invention shown secured to the ram plate of a punch press. FIG. 2 is a view taken along the line 22 thereof. FIG. 3.*is a section takenon 4theline 3-3 of FIG. 1. FIG. 4 is .a detail showing a step in the fabrication ofthe dierset of the presen-t invention. 4 l 4 FIG. 5 is a sectionof a punch prior t-oit being secured in the punch plate. FIG. 6 is a section of the'punch of FIG. 5 secured in the punch plate.

FIG. 7Vis` a section of a die member secured in the die plate. 7

FIG. 8 is a plan of a die. FIG. 9 is a plan of another die. Y Referring tothe drawing7 the dieset of the present in- A3,186,284 VPatented June l,V 1965 icethe undercut collar of the'. punches and die Vmembers to thereby securely fasten the punches and die members in their respective plates. i

Other features and advantages will hereinafter appear.

vention is generally indicated by the reference numeral 10 and include-s a punch plate 1v1 and a die plate 12 that are lsubstantially 'coextensive Thetvvo plateslll and 12 are parallel and mounted for movement towards and away -fromfeach other by guide pins `lisecured to the punch plate and operating inz guide bushings 14 secured to the die plate. A spring 15 encircles each'loftheguide pinsand urges the tvv-o plates apart while retaining means, such as @ring 16,' snap into a circular groove-17 formed in each of the guide pins to pre-vent separation'of the plates.

The die set 10, as shown in FlGxlfis secured to avr-am plate 18 of a punch press having a stationary steel pad l19. 1 Screws Ztlpass throughaperturesyll formed at opposite l cornersof the punch plate and are threaded into threaded apertures 22 formed in the ram .plate to thereby securelyv hold the die set '10 to the ram plate formovement therewith. Holes 23 formed in the dieplate 12 accommodate the head ofthe screws 2li when the plates'are moved t0- gether and'enable the die set tc besecured to the ram plate without disassembiing the set.` Moreover, Vit willbe v clear that the steel pad 19 is formed to have apertures 24 that accommodate the ends of the guide pins during the punching operation.

In the specific embodiment of the invention shown, the die 4set includes a plurality of punches Z5 secured to the punch plate llland a plurality of die members or dies 25 secured in the die plate 12, there being one die for each punch. The specic embodiment ofthe die set of the present invention is designed to punchthree circular holes of approximately the same size ina slightly triangular pattern.. It will be appreciated that any desired size of perforations land relative position may be punched inja piece by simply using'the required size punches and die members secured in their respective plates at the proper location. Moreover, for perforating a different size of piece a different-size of the plates 1-1 and 12 may be used than ythe size herein described. v a; In carrying out. the present invention, FIG. 6, each of the punches Z5 is secured to the punch plate 'by the punch having a portion 27 of the punch plate displaced into an undercut collar 28 of the punch 25. .The collar 2id is located between a head 29 and a stem 30with the punching portion 3d extending therebeyond. The diameter o f the stern portion 30 is somewhat smaller than the head por-tion 29 and yet is larger than the undercut collar 28. It will be .appreciated that the punch 2S is accordingly held securely in the punch plate 11 and also that the head o-f the punch is flush with the sur-V aperture 312 (FIG. 5) is'initially formed in the punch plate and the material displaced by the head is forced into Y plate v11 in thelocatic'n wherev it is 'desired to have a perforation formed in a piece (not shown). The size of the aperture 32 is approximately that of the stem 30 and a punch 25 is placed in the aperture 32. After an aperture 32 has been formed for each perforation to be made in the piece and a punch 25 of the correct size positioned therein, the punches are pressed into the die plate to force the material 33 of the punch plate under 4the head 29 of the punch Z5 into the undercut collar 28 to thus form the holding portion 27. It is contemplated to force all the punches into the punch plate in one pressing operation,l

After the securing of the punches 25 within the punch plate, the die plate is then aligned therewith lby the guide pins and a mark Vis made in the die plate, as shown in FIG. 4, by-a` central projection 34 on each of the punches. The die plate 12 is then removed and an aperture 35 (FIG. 7 formed therein to receive a die 26. The die has a construction similar to that of the punch inthat it has a head 36, an undercut collar '37 and a stern 3S with the stem .33 having a diameter substantially the same as the hole 35 but yet larger than the undercut collar 37 and smaller than the head 36 so that a holding portion 39 of the die plate is circumferentially forced into the undercut collar to secure the die in the die plate. The diameter of a through aperture 40 of each die is substantially that of the punching portion 31 of the punch 25 cooperating with each die.

It is presently preferned to also secure the guide pins 13 and guide bushings 14 in a similar manner such that they can also be secured by a simple pressing operation. Thus they would each include a head, an undercut collar and a stem.

To complete the die there is a-dditionally provided at selected positions locating guide pinsl 41 secured in the die plate 1-2, locating pin holes 42 formed in the plate 11 and a resilient stripping member 43.

In the present invention, the punch plate and the die plate are formed of a material softer than the material forming the punches 25 and die members 26 and is preferably aluminum, both of which may be of the same thickness. However, in the embodiment herein disclosed, the die plate is shown about twice the thickness of the punch plate, the latter being for example approximately s of an inch thick. The material from which the punches and the die members are made is harder than the plates 11 and 12 so that the plates distort when the punches and die members are forced therein rather than the latter distorting. The material may be a prehardened high strength steel capable of being easily machined (as by an automatic screw machine) requiring no further heat treatment. It is presently desired that the guide pins and the guide bushings also be formed of this mate- Irial.

While each of the punches 25 have been shown approximately the same, it will be clear that the punches and die members are made to have a diameter of the punching portion 31 which would form a perforation of the desired size in the piece. Moreover, it is also clear that the location of the punches will also be determined by the perforations to be formed in the piece.

Shown in FIG. 8 is ya cluster die 44 which may be employed according to the present invention for forming a plurality of small, closely spaced perforations in the piece rather than having .independent die members for each perforation. Additionally if any other than a round perforation is to be formed in the piece, the die and punch may be easily machined to have the shape of the desired perforation such as the square aperture 45 shown in a yshaped die 46 of FIG. 9.

It will yaccordingly be appreciated that in all forms of the invention herein disclosed that both the punches and the die members Whether ofsingle perforation forming or cluster forming, or shaped are provided with an unpunch each punch and die being secured by pressing the head into the plate to distort material into the undercut collar.

In use, with the die set fastened to the nam plate of the press and a piece positioned in the die set by the operator at a predetermined locality determined by the locating pins, the ram plate 18 is brought towards the steel pad 19 foncing the punches 25 into the die members 26 to thereby shear the perforations in the piece. When the ram plate 18 is retracted to the position shown in FIG. 1, the stripping member 43 will free the piece from the punches 25 permitting removal thereof while the slugs formed by the punches will rest on the steel pad 19 and may be easily removed by an air blast.

It will .be appreciated that the surface of the punch plate 1v1 that engages the ram plate 18 is dat with the heads 29 of the punches being substantially flush with this surface while the bottom surface of the die plate except for the ends of the guide pins is also flat thereby providing even pressure distribution throughout the two plates. Moreover, if after some usage it has been found that the cutting edges of the punches and the die members are becoming dull they may be effectively sharpened by removal of the C-ring 16, separating of the plates and a grinding of the top surface of the die members and of the cutting surface of the punches. The top surface of the head of each die member is substantially ush with the top surface of the die plate to facilitate the sharpening and also the positioning of the piece.

From the foregoing it will be appreciated that there has been disclosed a die set which is economical to fabricate and which is effective to produce short-run quantities of perforated pieces. One feature which enables achievement -of these advantages is the provision of formdercut Collar located between a head and a stem with ring each of the punches and die members to have an undercut ycollar into which portions of their respective punch and die plates are forced to thereby securely maintain these pieces in position. The plates are quickly and economically prepared to receive the punches and die member by merely forming holes therein, as by punching or drilling, at t-he localities wherein it is desired to form perforations in the piece. l

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used Without others.

I claim:

1. A punching die set for forming perforations in relatively thin material comprising a substantially fiat punch plate, a substantially llat die plate, means mounting the punch plate and die plate in parallel for movement toward and away from each other, this mounting means including guide pins at diagonal corners of the punch and die plates for alignment of the two plates, at least one aperture formed in the punch plate, a punch mounted in the aperture of the punch plate, said punch including a head, an undercut collar and a stem with the stem having a cross-section approximately that of the aperture and being larger than the collar but smaller than the head, the punch being secured in the punch plate by the head being forced into the punch plate to displace material of the punch plate around and into the undercut collar, said die plate being formed of relatively soft material and said punch being formed of relatively hard prehardened machineable steel alloy material.

2. A punching die set for forming perforations in relatively thin material comprising a substantially flat punch plate, a substantially flat' die plate, means mounting the punch plate and die plate in parallel for movement toward and away from each other, the mounting means including guide pinsat diagonal corners of the punch and die plates for alignment of the two plates, at least one punch mounted in the punch plate, at least one die mounted in the die plate for cooperation with the punch, the punch and die each including a head, an undercut collar and a stem with the stem being of larger cross-section than the collar but smaller than the head,

the punch and die being formed of prehardened machineable steel alloy and being secured in their respective plates by a portion of their respective plates being around and in the undercut collar.

3. The invention as defined in claim 2 in which the head of the die and the head of the punch are recessed into their respective plates to be at least flush therewith.

4. The invention as defined in claim 2in which the means for mounting includes a guide pin and a guide bushing with one being secured'in one plate and the other being secured in the other plate, said guide pin and said guide bushing each having a head, an undercut collar and a stem with the stem being larger in crosssection than the collar but smaller than the head, said guide pin and said guide bushing being secured in their respective plates by a portion of their respective plates being forced in and around the undercut collar.

5. A punching die set for forming perforations in relatively thin material comprising a substantially flat punch plate, a substantially iiat die plate, said plates being formed of relatively soft metal, means mounting the punch plate and die plate in parallel for movement toward and away from each other, the mounting means including guide pins at diagonal corners of the punch and die plates for alignment of the two plates, at least one punch mounted in the punch plate, at least one die mounted in the die plate for cooperation With the punch, the punch and die each including a head, an undercut collar and a stem with the stem being larger in crosssection than the collar but smaller than the head, the,`

punch and die being secured in their respective plates by each head being forced into the plate to displace a portion of their respective plates around and into the undercut collar, said punch and die being made of a relatively hard prehardened machineable steel alloy metal. Y

-6. The invention -as deined in claim 5 -in which the plate material is aluminum..

7. A punch for use in a punching die set for forming periorations in relatively thin material comprising a head, a stem and an undercut collar positioned between the Vhead and the stem, the cross-sectional periphery of the stem being larger than that of the undercut collar but being smaller than that of the head, the stem including a punching portion, said punch being formed in one piec from a prehardened, machinable steel alloy.

.References Cited bythe Examiner UNITED STATES PATENTS 1,179,476 4/16 Thomas 83-686 1,767,492 6/ 30 Valentine 83-687 1,946,065 2/ 34 Dodge 151-41.73 1,959,602 5/ 34 Stanbon 83-623 2,017,247 10/35 Hodge 83-686 2,195,598 4/40 Olson 15l-41.73 y2,359,682, 10/44 Ruder 83-685 2,372,485 3/ 45 Griiiin 8,5-21 2,374,436 4/ 45 Kennedy et al 83-139 2,381,062 8/ 45 Kirsch 83-637 2,553,615 5/51 Wales 83-139 FOREIGN PATENTS 470,931 8/ 37 Great Britain LEON PEAR, Primary Examiner.

CARL D. TOMLIN, HUNTER C. BOURNE, JR.,

WILLIAM W. DYER, IR., Examiners. 

1. A PUNCHING DIE SET FOR FORMING PERFORATIONS IN RELATIVELY THIN MATERIAL COMPRISING A SUBSTANTIALLY FLAT PUNCH PLATE, A SUBSTANTIALLY FLAT DIE PLATE, MEANS MOUNTING THE PUNCH PLATE AND DIE PLATE IN PARALLEL FOR MOVEMENT TOWARD AND AWAY FROM EACH OTHER, THIS MOUNTING MEANS INCLUDNG GUIDE PINS AT DIAGONAL CORNERS OF THE PUNCH AND DIE PLATES FOR ALIGNMENT OF THE TWO PLATES, AT LEAST ONE APERTURE FORMED IN THE PUNCH PLATE, A PUNCH MOUNTED IN THE APERTURE OF THE PUNCH PLATE, SAID PUNCH INCLUDING A HEAD, AN UNDERCUT COLLAR AND A STEM WITH THE STEM HAVING A CROSS-SECTION APPROXIMATELY THAT OF THE APERTURE AND BEING LARGER THAN THE COLLAR BUT SMALLER THAN THE HEAD, THE PUNCH BEING SECURED IN THE PUNCH PLATE BY THE HEAD BEING FORCED INTO THE PUNCH PLATE TO DISPLACE MATERIAL OF THE PUNCH PLATE AROUND AND INTO THE UNDERCUT COLLAR, SAID DIE PLATE BEING FORMED OF RELATIVELY SOFT MATERIAL AND SAID PUNCH BEING FORMED OF RELATIVELY HARD PREHARDENED MACHINEABLE STEEL ALLOY MATERIAL. 